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SWG Cell not working?

I've had a Jandy SWG for 2.5 years - love the thing. Over the past two month, though, I've had major trouble keeping the FC level up. I know the first thing you think of is CYA level. I've had it checked numerous time, myself with both the test strips and the TF-100 kit, and at the local Leslie's pool, and the level seems ok (around 70). Everything else chemically is perfect, but still can't get the chlorine level up. We've dumped a lot of liquid into the pool lately, which will get the level up slightly, but 24 hours later it's gone. I've checked the SWG cell and it looks great, hardly any buildup at all. Can it just go bad and not generate any FC?

Re: SWG Cell not working?

It could, but if you're losing a substantial amount of chlorine over 24 hours then there's probably something consuming it faster than the SWG can generate it. How much have you been losing? Do an overnight FC test to see if you lose any chlorine while the sun is down. If so, bring your pool up to shock level with liquid chlorine (about 30ppm for you) and hold it there until you're no longer losing chlorine overnight.

And just to be sure, get your salt level tested to double check the cell's reading.

Re: SWG Cell not working?

I actually did a separate salt level test and it matched what the SWG sensor was reading (3600-3700) which is slightly above what Jandy recommends (3500). So I figured I was good there too. I'll max out the chlorine and see if that helps. Should have mentioned that two large areas of black algae have formed over the past three weeks. They retreat with the chlorine hits (I do brush them before I add the chlorine), but have yet to totally disappear.

Re: SWG Cell not working?

Originally Posted by hillyjd

I actually did a separate salt level test and it matched what the SWG sensor was reading (3600-3700) which is slightly above what Jandy recommends (3500). So I figured I was good there too. I'll max out the chlorine and see if that helps. Should have mentioned that two large areas of black algae have formed over the past three weeks. They retreat with the chlorine hits (I do brush them before I add the chlorine), but have yet to totally disappear.

Hello Hillyjd and welcome to the forum...

Please read Defeating Algae in Pool School. I'm not familiar with the Jandy SWG you have on your pool but I can tell you that if the output is equivalent to the Hayward Aqua cell (producing about 1.45 lbs chlorine per day) you may never be able to get enough chlorine from the SWG to completely rid yourself of the algea... As spishex indicated, you'll have to introduce enough chlorine to get to very high shock levels, and then keep it there until the algea is all dead. This almost always necessitates the addition of liquid chlorine or 6% bleach == and in quantities. Would suggest following sphishex's succinct and specific recommendations. Good luck!

Re: SWG Cell not working?

To truly defeat the algae, you'll need to get the chlorine up to shock level which is dependant on your cya (see this chart). 10 ppm chlorine is shock for 20 ppm cya. If your cya is actually 70 ppm, you're WAY short of shocking your pool (referenced chart says shock level = 28). Remember shocking your pool is a process, not a product!

Re: SWG Cell not working?

I've been gone quite a bit lately and didn't get a chance to follow up. No matter how much chlorine I put in the pool, it was gone within a day or two. Then I noticed that I was getting an error code 178/182 on the SWB control box. I had seen this before and it would clear after I cleaned the sensor, which I did, but the error returned a day or two later, and was intermittent. To make a long story short, I finally ended up replacing the sensor, and now I have more chlorine in the pool than I can get rid of. I now believe the sensor was failing intermittently, which I am told by Jandy will turn off the cell. Working great (almost too good) now.

It sure sounds like you've got something trying to thrive in the pool Please follow the advice given to rid the pool of it and I'll bet you are back to a trouble free pool [/quote]